Field
Exemplary embodiments of the present disclosure relate to a light emitting diode package. More particularly, exemplary embodiments of the present disclosure relate to a light emitting diode package including a molding portion having high strength.
Discussion of the Background
A light emitting diode (LED) package refers to a compound semiconductor device having a p-n junction structure and emitting light through recombination of carriers (electrons or holes). The light emitting diode package has low power consumption and long lifespan and can be fabricated in a small size.
A light emitting diode package can realize white light through wavelength conversion means including phosphors. Specifically, the phosphors are disposed above a light emitting diode chip such that the light emitting diode package can realize white light through mixture of some of primary light emitted from the light emitting diode chip and secondary light subjected to wavelength conversion by the phosphors. With this structure, the white light emitting diode package is broadly used due to advantages of inexpensiveness and a simple structure.
Specifically, the light emitting diode package can realize white light by depositing phosphors, which emit yellowish green or yellow light through absorption of some of blue light as excitation light, on a blue light emitting diode chip. Korean Patent Laid-open Publication No. 10-2004-0032456 discloses a light emitting diode, in which phosphors are deposited on a blue light emitting diode chip to emit yellowish green or yellow light using some light emitted from the blue light emitting diode as excitation light such that the light emitting diode can emit white light through mixture of the blue light and the yellowish green or yellow light.
However, since such a white light emitting diode package uses light emission of yellow phosphors, the white light emitting diode has low color rendition due to spectrum depletion in green and red regions of light emitted therefrom. Particularly, in use of the white light emitting diodes as a light source of a backlight unit, it is difficult to realize a color approaching a natural color due to low color purity after light passes through a color filter.
In order to solve such problems, a light emitting diode is fabricated using a blue light emitting diode chip and phosphors emitting green and red light using blue light as excitation light. That is, it is possible to realize white light having high color rendition through mixture of blue light and green light and red light, which are excited by the blue light. In a structure wherein such a white light emitting diode is used in a backlight unit, it is possible to realize an image approaching a natural color due to high conformity with the color filter. However, light emitted from the phosphors through excitation by the phosphors has a wider full width at half maximum than light emitted from the light emitting diode chip. Korean Patent Registration No. 10-0961324 discloses nitride phosphors, a method of preparing the same, and a light emitting device. In luminous spectra of a light emitting device including nitride phosphors, it can be seen that light emitted from the light emitting device has a wider full width at half maximum in the red band.
Accordingly, it is necessary to use phosphors having a narrower full width at half maximum in order to realize white light having higher color rendition. However, the phosphors having a narrower full width at half maximum are generally vulnerable to moisture, thereby causing deterioration in overall reliability of the light emitting diode package.